Or at least that's what the mischief-maker led his co-stars to believe.

During filming, Pegg convinced pretty much everyone -- from Zachary Quinto to Zoe Saldana to John Cho -- that they needed to apply a special ointment called Neutron Cream to their faces to shield themselves from potentially harmful ions in the laser room. He even went as far as having folks sign waivers, Benedict Cumberbatch included.

Naturally, the elaborate prank was caught on tape, and the footage of the actors with little dots of cream on their faces is as amazing as it sounds.

Back in early May, Cumberbatch admitted to BBC TV host Graham Norton that he fell for the gag. "We were in a really futuristic laboratory with lasers that were trying to split a target smaller than a human hair to create a continual form of energy," he said. "And I was like, 'Wow, this is the real deal, what can't we touch? What's safe?' I got on set and was told I needed to wear 'Neutron Cream' to protect me. I was gullible and did what I was told; it's America and there is a lot of health and safety."